The application of web material to objects, and more particularly the application of adhesive tapes to objects, by automatic devices, semi automatic devices, and manual devices is well known. Moreover, many dispensing apparatuses have been designed which are either hand held and portable or are fixed relative to a product line. In either case, such devices typically include mechanisms for cutting and applying the tape or similar web material to the object.
In order to present the tape or web material to a point that facilitates the application of the tape or web material to an object, it is also known to provide feeding mechanisms to dispensing devices which drive the tape or web material along its path through the dispenser to an application point. This is typically done after the previous length of tape or web material is applied to a preceding object so that the tape or web material is available for application to a subsequent object.
A problem associated with the feeding of such tapes or web material is that the feeding should not occur until after the cutting mechanism has cleanly severed the previous length of tape and has gotten out of the way of the leading edge of the supply of tape. If the feeding mechanism drives the tape forward before the cutting mechanism has cleared the path of the tape, the leading edge of the tape may strike the cutting mechanism and the device could jam. Thus, typically the cutting mechanism and the feeding mechanism are controlled separate from one another and are each associated with some control system which permits the advance of the leading edge of the tape only after the cutting mechanism has cleared the path that the tape will follow.
A specific example of a tape applicator including a cutting mechanism and a feeding mechanism wherein the feeding is delayed until after the cutting mechanism clears the tape path, has been used in the Scotch.TM. S-625 Pad Applicator available from Minnesota Mining and Manufacturing Company of St. Paul, Minn. Specifically, the cutting mechanism which also forms a part of the applying pad mechanism for applying the cut length of tape to an object is controlled by an actuator device comprising an air cylinder. A separate feed mechanism comprising an electric motor and a feed wheel are also provided for advancing the leading edge of the tape only after the cutting mechanism and the applying pad are retracted sufficiently from the path of tape advance. In order to time the mechanisms together, an electric circuit is utilized for driving the electric motor and thus the feed wheel only after a limit switch is actuated by the cutting mechanism when it is sufficiently retracted. In other words, separate cutting and feeding mechanisms are provided which relate to one another via a control system comprising an electrical circuit and limit switch. Although such devices function satisfactorily, they are fairly complex and expensive requiring the combination of drive mechanisms, sensing devices and actuators.
The problem of feeding tape or web material in conjunction with a cutting mechanism is further exasperated when relatively thick tapes or web material are to be dispensed. When a thick tape or web material is dispensed, the cutting mechanism needs a relatively long stroke in order to sever the entire thickness of the tape or web material and the feeding mechanism must be delayed until the cutting mechanism is entirely clear from the thickness of the tape or web material. An example of a thick tape to which the present invention is particularly applicable is a foam tape. Foam tapes typically comprise a strip of foam material having a thickness of at least 0.005 inch and include a layer of adhesive on one side of the foam material. Such foam tapes may also comprise an additional layer of adhesive on the other side thereof and may yet be covered with a cover strip.
One specific tape dispenser specifically directed to the dispensing and application of foam tapes is disclosed is U.S. Pat. No. 5,068,004, granted Nov. 26, 1991 to Moll, which is commonly owned by the assignee of the present invention. The Moll device includes a specific cutting blade for severing tape lengths, but does not include a feeding mechanism for advancing the tape to an application point thereof. Instead, after a length of tape is applied to an object by moving the device along the object, a trigger is squeezed and the width of the tape is only partially cut. Thereafter, an additional length of tape is dispensed by moving the dispenser past the object and thus pulling more tape from the supply, and after a sufficient amount is advanced, a brake mechanism is actuated by the trigger to stop dispensing of the tape. Then, the operator pulls against the applied tape with the brake applied to tear the unsevered portion at the tape cut. The problem with this type of dispenser is that the method of application requires specific operator steps including the pulling of the trigger mechanism twice for each single length of tape dispensed.
Clearly, there is a need for a tape dispenser which can facilitate all tapes and web materials including thick tapes and web materials which is less complex than the control systems associated with the prior art and which can be more easily manipulated by an operator to control both cutting and feeding of the tape without jamming the dispenser.